diff --git a/cheroot/workers/threadpool.py b/cheroot/workers/threadpool.py
index 795ebc6d53..bd784b85ff 100644
--- a/cheroot/workers/threadpool.py
+++ b/cheroot/workers/threadpool.py
@@ -178,7 +178,7 @@ def start(self):
         for worker in self._threads:
             worker.name = (
                 'CP Server {worker_name!s}'.
-                format(worker_name=worker.name),
+                format(worker_name=worker.name)
             )
             worker.start()
         for worker in self._threads:
@@ -228,7 +228,7 @@ def _spawn_worker(self):
         worker = WorkerThread(self.server)
         worker.name = (
             'CP Server {worker_name!s}'.
-            format(worker_name=worker.name),
+            format(worker_name=worker.name)
         )
         worker.start()
         return worker